Solid-state transducer devices with selective wavelength reflectors and associated systems and methods

Abstract

Solid state transducer (“SST”) devices with selective wavelength reflectors and associated systems and methods are disclosed herein. In several embodiments, for example, an SST device can include a first emitter configured to emit emissions having a first wavelength and a second emitter configured to emit emissions having a second wavelength different from the first wavelength. The first and second emitters can be SST structures and/or converter materials. The SST device can further include a selective wavelength reflector between the first and second emitters. The selective wavelength reflector can be configured to at least substantially transmit emissions having the first wavelength and at least substantially reflect emissions having the second wavelength.

We claim: 
     
       1. A solid-state transducer (SST) device, comprising:
 a first emitter configured to emit first emission having a first wavelength; 
 a second emitter configured to emit second emission having a second wavelength different from the first wavelength; and 
 a selective wavelength reflector having a front surface facing a front side of the SST device from which the first and second emissions exit the SST device, and a back surface facing a back side of the SST device opposite to the front side, the first emitter being at the back surface and the second emitter being at the front surface, wherein:
 the selective wavelength reflector is configured to at least substantially transmit the first emission and at least substantially reflect the second emission; and 
 the selective wavelength reflector includes a multilayer stack of materials comprising layers of silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), and alloys thereof, two TiO 2  layers of the multilayer stack being separated by a SiO 2  layer and at least one alloy layer, 
 
 wherein the first emitter includes an SST structure having a first semiconductor material comprising N-type gallium nitride (N-GaN), a second semiconductor material comprising a P-type gallium nitride (P-GaN), and an active region comprising indium gallium nitride (InGaN), the active region being between the first and second semiconductor materials; 
 wherein the SST structure is configured to emit blue light; 
 wherein the second emitter includes a converter material configured to emit yellow light; and 
 wherein the selective wavelength reflector is configured to at least substantially transmit the blue light and at least substantially reflect the yellow light. 
 
     
     
       2. A solid-state transducer (SST) device, comprising:
 a first emitter configured to emit first emission having a first wavelength; 
 a second emitter configured to emit second emission having a second wavelength different from the first wavelength; and 
 a selective wavelength reflector having a front surface facing a front side of the SST device from which the first and second emissions exit the SST device, and a back surface facing a back side of the SST device opposite to the front side, the first emitter being at the back surface and the second emitter being at the front surface, wherein:
 the selective wavelength reflector is configured to at least substantially transmit the first emission and at least substantially reflect the second emission; and 
 
 the selective wavelength reflector includes a multilayer stack of materials comprising layers of silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), and alloys thereof, two TiO 2  layers of the multilayer stack being separated by a SiO 2  layer and at least one alloy layer, 
 wherein the first emitter is an SST structure configured to emit blue light; 
 wherein the second emitter is a first converter material configured to emit red light; 
 wherein the selective wavelength reflector is a first selective wavelength reflector configured to at least substantially transmit the blue light and at least substantially reflect the red light and green light toward the front side of the SST device; and 
 wherein the SST device further comprises:
 a second converter material proximate the front side of the SST device with respect to the first converter material, the second converter material being configured to emit the green light; and 
 a second selective wavelength reflector between the first and second converter materials, wherein the second selective wavelength reflector is configured to at least substantially transmit the blue and red light and at least substantially reflect the green light toward the front side of the SST device. 
 
 
     
     
       3. The SST device of  claim 1 , wherein:
 the first emission has a first energy; and 
 the second emission has a second energy less than the first energy. 
 
     
     
       4. The SST device of  claim 1 , wherein the first wavelength is shorter than the second wavelength. 
     
     
       5. The SST device of  claim 1 , wherein each material of the multilayer stack of materials has a thickness and a refractive index such that a combination of the materials in the multilayer stack at least substantially transmits the first emission and at least substantially reflects the second emission toward the front side of the SST device. 
     
     
       6. The SST device of  claim 1 , wherein the multilayer stack of materials of the selective wavelength reflector further comprises fluoride glasses. 
     
     
       7. The SST device of  claim 1 , further comprising:
 a spacer separating the selective wavelength reflector from the first emitter or from the second emitter, wherein the spacer includes a substantially transmissive nonconductive material to the first and second emissions. 
 
     
     
       8. The SST device of  claim 7 , wherein:
 the first emitter includes an active region having a first dimension, across which the first emission is emitted; and 
 the spacer includes a second dimension that is substantially parallel to and same as the first dimension. 
 
     
     
       9. The SST device of  claim 1 , wherein the at least one alloy layer comprises an alloy layer including approximately 7% titanium dioxide. 
     
     
       10. The SST device of  claim 1 , wherein the at least one alloy layer comprises an alloy layer including approximately 54% titanium dioxide. 
     
     
       11. A solid-state transducer (SST) device, comprising:
 an SST structure configured to emit first emission having a first wavelength; 
 a converter material structure configured to emit second emission having a second wavelength different from the first wavelength; and 
 a selective wavelength reflector between the SST structure and the converter material structure, wherein:
 the selective wavelength reflector has a refractive index configured to at least substantially reflect the second emission and at least substantially limit reflection of the first emission; and 
 the selective wavelength reflector includes a multilayer stack of materials comprising layers of silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), and alloys thereof, two TiO 2  layers of the multilayer stack being separated by a SiO 2  layer and at least one alloy layer, 
 
 wherein the SST device has a front side from which the first and second emissions exit the SST device and a back side facing away from the front side; 
 the converter material structure comprises a plurality of converter materials proximate the front side of the SST device with respect to the SST structure, the converter materials of the plurality being configured to emit emission with successively shorter wavelengths as the converter materials of the plurality are positioned closer to the front side of the SST device; 
 the selective wavelength reflector is a first selective wavelength reflector; and 
 the SST device further comprises:
 a plurality of second selective wavelength reflectors between adjacent converter materials of the plurality, each second selective wavelength reflector having a second refractive index configured to at least substantially reflect emission of the overlying converter material(s) and at least substantially limit reflection of emission of the underlying converter material(s). 
 
 
     
     
       12. The SST device of  claim 11 , wherein:
 the first wavelength ranges from about 420 nm to about 480 nm; and 
 the second wavelength ranges from about 480 nm to about 750 nm. 
 
     
     
       13. The SST device of  claim 11 , further comprising:
 a spacer separating the selective wavelength reflector from the SST structure or from the converter material structure, wherein the spacer is configured to be substantially transmissive to the first and second emissions. 
 
     
     
       14. A light emitting diode (LED) device, comprising:
 an LED structure configured to emit first light having a first wavelength; 
 an emitter configured to emit second light having a second wavelength different from the first wavelength; and 
 a selective wavelength reflector having a front surface facing a front side of the LED device from which the first and second light exit the LED device, and a back surface facing a back side of the LED device opposite to the front side, the LED structure being at the back surface and the emitter being at the front surface, wherein:
 the selective wavelength reflector is configured to at least substantially transmit the first light and at least substantially reflect the second light; and 
 the selective wavelength reflector includes a multilayer stack of materials comprising layers of silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), and alloys thereof, two TiO 2  layers of the multilayer stack being separated by a SiO 2  layer and at least one alloy layer, 
 
 wherein the emitter comprises a plurality of converter materials proximate the front side of the LED device with respect to the LED structure, the converter materials of the plurality being configured to emit light having successively shorter wavelengths as the converter materials of the plurality are positioned closer to the front side of the LED device; 
 wherein the selective wavelength reflector is a first selective wavelength reflector; and 
 wherein the LED device further comprises a plurality of second selective wavelength reflectors between adjacent converter materials of the plurality, each second selective wavelength reflector having a refractive index configured to at least substantially reflect light emitted by the overlying converter material(s) and at least substantially limit reflection of light emitted by the underlying converter material(s). 
 
     
     
       15. The LED device of  claim 14 , wherein:
 the LED structure is configured to emit blue light; 
 the emitter includes a converter material configured to emit yellow light; and 
 the selective wavelength reflector is configured to at least substantially transmit the blue light and at least substantially reflect the yellow light. 
 
     
     
       16. A light emitting diode (LED) device, comprising:
 an LED structure configured to emit first light having a first wavelength; 
 an emitter configured to emit second light having a second wavelength different from the first wavelength; and 
 a selective wavelength reflector having a front surface facing a front side of the LED device from which the first and second light exit the LED device, and a back surface facing a back side of the LED device opposite to the front side, the LED structure being at the back surface and the emitter being at the front surface, wherein:
 the selective wavelength reflector is configured to at least substantially transmit the first light and at least substantially reflect the second light; and 
 
 the selective wavelength reflector includes a multilayer stack of materials comprising layers of silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), and alloys thereof, two TiO 2  layers of the multilayer stack being separated by a SiO 2  layer and at least one alloy layer, 
 wherein the LED structure is configured to emit blue light; 
 wherein the emitter is a first converter material configured to emit red light; 
 wherein the selective wavelength reflector is a first selective wavelength reflector configured to at least substantially transmit the blue light and at least substantially reflect the red light and green light toward the front side of the LED device; and 
 wherein the LED device further comprises:
 a second converter material proximate the front side of the LED device with respect to the first converter material, the second converter material being configured to emit the green light; and 
 a second selective wavelength reflector between the first and second converter materials, wherein the second selective wavelength reflector is configured to at least substantially transmit the blue and red light and at least substantially reflect the green light toward the front side of the LED device. 
 
 
     
     
       17. The LED device of  claim 14 , wherein each material of the multilayer stack of materials has a thickness and a refractive index such that a combination of the materials in the multilayer stack at least substantially transmits the first light and at least substantially reflects the second light toward the front side of the LED device.